On 3rd March 1945 there was carried out the first flight of a Soviet fighter MiG I-250 with jet and airscrew propulsion. Using hybrid propulsion was caused by little experience of the constructors with jet propulsion and lack of suitable turbojet engines. During test flights the aircraft reached the speed of 825 km/h. The aircraft was able to carry three 20mm cannons. Because of the problems with power unit and more advanced projects of jet aeroplanes the series production of MiG I-250 was stopped.